Blog & Notes
Software guides, educational content, travel notes, and personal experiences
Total 127 posts
SwiftUI @State, @Binding and @Observable: Data Flow Guide
When to use @State, @Binding, @Observable, @Bindable and @Environment in SwiftUI, how they map to ObservableObject, with a decision table and common bugs.
Swift Struct vs Class: Value and Reference Types Explained
Learn the difference between struct and class in Swift with runnable examples: copying, mutating, let, ===, inheritance, deinit and how to choose.
Swift Closures Explained: $0, @escaping and [weak self]
Learn Swift closure syntax step by step from the full form to $0 shorthand: trailing closures, capturing values, @escaping, retain cycles and [weak self].
Swift async/await Guide: Tasks, Actors and @MainActor
From completion handlers to async/await: Task, async let, TaskGroup, @MainActor, actors, cancellation and a JSON API call with URLSession in SwiftUI.
Sorting Algorithms Exam Questions with Worked Solutions
Bubble, selection, insertion, merge and quick sort: one comparison table, pass-by-pass array traces and 8 exam questions solved step by step.
Seoul Climate Card: Unlimited Subway and Bus Pass Guide
Seoul Climate Card: 5-day pass for 15,000 won plus 3,000 won card. Unlimited subway and buses, prices, where to buy and where it doesn't work.
Recapday Couple Mode: Why a Two-Person Group Needed Its Own Mode
How Couple Mode found its way into Recapday: what changes at two people, why a mode beat a separate app, and what I deliberately left out.
C# Interface vs Abstract Class: Differences and When to Use
C# interface vs abstract class: what each can contain, multiple interfaces, a decision guide, a payment example and typical exam questions with answers.
C# Inheritance and Polymorphism: virtual, override and new
C# inheritance and polymorphism guide: base, constructor chaining, virtual/override vs new, sealed, is/as and the classic "what does this print?" question.
SwiftUI First App: A Step-by-Step Guide for Beginners
Build your first SwiftUI app from an empty Xcode project to the simulator: App, View, VStack, @State, List and TextField in a working to-do list.
Binary Search Tree Exam Questions: Insert, Delete, Traverse
The BST property, insert, search and delete, inorder/preorder/postorder traversal, height and the degenerate case; 7 exam questions with drawn trees.
Big O Notation and Time Complexity: A Practical Guide
What Big O means and how to find the complexity of loops and recursion: O/Ω/Θ, the Master theorem, space complexity and 8 solved exercises.
ASP.NET Core Minimal API: Build Your First REST API
Build a REST API from scratch with ASP.NET Core Minimal APIs: MapGet/MapPost, route parameters, TypedResults, dependency injection, validation, curl tests.
App Store Publishing Guide: From Xcode Archive to Review
From the Apple Developer account and App Store Connect record to TestFlight and review: how to publish an iOS app and the most common rejection reasons.
Money Exchange in Seoul: US$100 = 149,500 Won in Myeongdong
We got 149,500 won for US$100 in Myeongdong, far better than the airport. Rate tips, small buy-sell spread and a free toy for a Google review.
Urban Hotel & Play: 4 Nights in Sinchon, Seoul Review
Urban Hotel & Play in Sinchon, Seoul: 4 nights for about 10,000 TRY. Spotless rooms, free drinks, a 5-PC gaming room, 5 minutes to the subway.
Incheon Airport to Seoul: The Cheapest Way Into the City
AREX all-stop train for 4,750–5,350 won or the airport bus for about 17,000 won. Incheon to central Seoul transport options, travel times and a cash tip.
How to Get a K-ETA: Bangkok to Seoul Flight and Korea Entry
We flew Bangkok to Seoul with VietJet in about 6 hours. What the K-ETA is, what it costs, who is exempt in 2026, and how to avoid fake application sites.
13 Days in Thailand Cost: 29,009 TRY Excluding Flights
13 days in Thailand for 29,009 TRY excluding flights, about 2,231 TRY a day. Accommodation, food, transport and Pattaya costs itemized.
What Is Talkamble? Turn a Walk Into a Conversation
Can a solo walk become a natural conversation with someone who is walking at the same time? Here is how Talkamble works and why it puts voice ahead of the screen.
Voice-Chat App Safety: 8 Things to Check
Before speaking with someone new, use these eight checks to understand how an app handles accounts, location, mutual consent, reporting and personal data.
Can We Socialize Without Looking at a Screen?
Why do most social apps demand constant attention? A look at voice-first, screen-free social connection through the design decisions behind Talkamble.
A New Way to Find a Walking Companion
Walking is easy; going out consistently is harder. Talkamble explores a smaller, more practical idea than permanent plans: a voice that accompanies this walk.
Merging Videos on Device With ffmpeg: Turning Mixed Aspect Ratios Into One Vlog
Some vertical, some horizontal, some stills. How Recapday turns that mix into a single 1920x1080 vlog on the phone rather than on a server: blurred padding, non-ASCII text overlays, music, and compression I actually measured.
How I Built Recapday: A Decision Log From Idea to Store
The architectural decisions behind Recapday, a daily clip app for groups of friends: why identity lives in Firebase but data lives on my own server, why I deleted the social features, and which choices turned out to be irreversible.
Flutter Camera Without Forcing Orientation: Three Bugs and Their Fixes
A rotated preview, a freeze when recording starts, and a dead camera after pulling down notification centre. The three concrete bugs I hit building Recapday's camera screen in Flutter, and the code that fixed each one.
Firebase Auth With Your Own PHP Server: Token Verification and Account Deletion Without Composer
Identity in Firebase, data on your own server. So how does PHP decide to trust the incoming token? RS256 verification on shared hosting without composer, plus the account-deletion flow both app stores require.
What Is Claude Design? Seven Levels of AI Design
Most people stop at the first level of Claude Design and get generic results. Here are seven levels, the costly mistake at each one, and how to move up.
What Is a Harness? The Difference Between the Model and the Coding Tool (with DeepSeek)
Why does the same model behave completely differently in two tools? The answer is the harness. Using DeepSeek as the example, here is what a harness actually does — the agent loop, tool calling, and context management.
What Is an Agent Skill? How to Write Skills That Work
Most agent skills add little value. Learn the patterns that work, the rules for writing reliable skills, and the security checks to run before installation.
What Is AI Slop? Building a Website That Doesn’t Look AI-Generated
Why do AI-generated websites all look alike? Learn the signs of AI slop and practical ways to escape it through typography, imagery and copy.
Website Design Audit: Comparing Against a Reference
Can’t explain why your website falls short? Compare it with a strong reference and turn vague impressions into a concrete design audit.
AI Motion Graphics: Data, Icons and Automation
Why do AI-generated animations all look the same? Turn real data into motion, use quality assets, and generate graphics automatically from video.
Consistency in AI Design: The Critic Loop
AI-generated designs become inconsistent when the model grades its own work. Learn how an independent critic loop fixes this and what it costs.
What Is Vibe Coding? A Realistic Beginner's Guide
What is vibe coding, how does it work, which tools should you use? A practical starting point for anyone who wants to build apps with Claude, ChatGPT, Cursor, or Codex — written for real developers, not for hype.
Vibe Coding Tools Compared: When to Use Claude, ChatGPT, Cursor, and Codex
Which vibe coding tool should you pick? A hands-on comparison of Claude, ChatGPT, Cursor, Codex, and GitHub Copilot from real projects: strengths, weaknesses, and when to use each one.
The Vibe Coding Method: 7 Practical Tips and the Art of Writing Prompts
Seven tips that actually work in vibe coding: writing prompts, building a decision document, giving small tasks, protecting with tests, auditing, and refactoring. The formula to go from 'it works' to 'it keeps working'.
Shipping an App Store App with Full Vibe Coding: The LevelUpStudy Story
Can you actually ship an App Store app by coding with AI? Here is the method that worked while building LevelUpStudy, the three real walls I hit, and the lessons I took away.
What Is LevelUpStudy? A Study Tracker App for Exam Preparation
Do you actually know how many hours you study a day? Here is how LevelUpStudy turns exam preparation into something measurable with focus sessions, streaks, leaderboards and a 3D study desk.
Best Places to Visit in Pattaya: A 4-Day Local List
We spent 4 nights in Pattaya. Koh Larn's clear water, the Eiffel Tower in Terminal 21, Walking Street and a 250-baht motorbike, with real prices.
Best Places to Visit in Bangkok: A 7-Day Local List
We spent 7 nights in Bangkok. From Wat Arun to the 69-meter Big Buddha and the Dragon Temple, the places not to miss, with real prices and locations.
Emsphere Sky Beach Club and Terminal 21: Last Day in Bangkok
The free rooftop Sky Beach Club pool at Emsphere mall, a Honda scooter test ride, and Terminal 21 as our goodbye to Bangkok. Locations and prices.
Wat Phra Yai and Terminal 21: Big Buddha and an Eiffel Tower
We visited Wat Phra Yai, known as the Big Buddha, and its Yaksha guardians, then saw the Eiffel Tower inside Terminal 21. Locations and prices inside.
Koh Larn Island: Motorbike Tour and Beaches Near Pattaya
We took the ferry from Bali Hai Pier to Koh Larn, rented a motorbike for 250 baht and toured the island. Nual and Tawaen beaches, prices and routes.
Pattaya Day 1: Swensen's, Cafe Amazon and Walking Street
Our first day in Pattaya: Turkish breakfast, a beach walk, Cafe Amazon, the best ice cream at Swensen's RGP, and a night on Walking Street.
Beach by Anatolia Condo Suite: 4 Nights in Pattaya, 6,000 TL
Just 50 meters from the sea, 4 nights for 6,000 TL (~150 USD). Spotless rooms, a big pool, daily housekeeping and a location next to the mall.
Bangkok to Pattaya: The Cheapest Way, a 180-Baht Bus
We bought a 180-baht bus ticket on 12Go and left from Suvarnabhumi Terminal 2. E-ticket swap, the transfer-driver trap, and reaching your hotel by Bolt.
Wat Samphran Dragon Temple: Climbing Down a Giant Dragon
At Bangkok's pink Wat Samphran temple we rode the lift up 17 floors and climbed down inside the giant dragon. Entrance fee, transport and location.
32 Bar X, The Mall LifeStore and June Pang: Bangkok Day 5
32 Bar X, where they make their own chocolate, The Mall LifeStore full of million-dollar cars, and June Pang's creamy milk toast. Locations inside.
Wat Arun and Empire Tower: Coffee on Bangkok's 55th Floor
We explored Wat Arun, the temple clad in Chinese porcelain, then had coffee on the 55th floor of Empire Tower facing the skyline. Fees and locations.
Wat Paknam: The 69-Meter Giant Buddha in Bangkok
We visited the 69-meter seated Buddha statue at Wat Paknam in Bangkok. How to get there, entrance details and what to expect on your visit.
Wat Hong Temple and the Wat Arun Plan: Bangkok Day Two
On our second day in Bangkok, we visited Wat Hong Temple, met Buddhist monks, and saved Wat Arun for the next day.
ICONSIAM and Chinatown: Your First Day in Bangkok
Our first-day visit to ICONSIAM and Chinatown in Bangkok, including boat transport, the giant dog statue, musical fountains, and street food vibes.
Flutter: SliverAppBar for Sticky Headers and Search Bars
Use SliverAppBar in Flutter to create modern headers that collapse, stay pinned, and include a search bar.
Flutter: SliverAppBar for Category Headers and Search Fields
Use SliverAppBar to build category headers, search fields, and sticky top sections for scroll-based Flutter screens.
Flutter: SingleChildScrollView, ListView, NestedScrollView
Compare Flutter scroll widgets, understand performance tradeoffs, and solve nested scroll issues with better widget selection.
Flutter: Row and Column Alignment Control with mainAxisSize
Set mainAxisAlignment.center and nothing moved? How mainAxisSize, mainAxisAlignment and crossAxisAlignment work together in Row and Column, with fixes.
Flutter: Compact Dialogs and Button Groups with mainAxisSize
Is your dialog filling the whole screen? Ready-made recipes that use mainAxisSize.min to wrap dialogs, bottom sheets and button groups around their content.
Flutter: Responsive Breakpoint Design with LayoutBuilder
Build responsive Flutter interfaces for mobile, tablet, desktop, and web by using LayoutBuilder with a breakpoint-based design approach.
Flutter: Hero Animation Speed and Transition Timing
Control Flutter Hero animation speed, transition duration, and curve settings to create a smoother and more premium page transition experience.
Flutter: Hero Animation Errors and Best Practices
Learn how to avoid duplicate tags, Material mismatches, and broken transitions in Flutter Hero animations.
Flutter: Layout Control with Expanded, Flexible, and Spacer
Four ready-made recipes combining Expanded, Flexible and Spacer: a toolbar, a card footer, form rows and a responsive split screen, with the reasoning.
Flutter: Expanded, Flexible, and Spacer Compared
Learn the difference between Expanded, Flexible, and Spacer in Flutter to avoid layout issues and control space distribution correctly.
Flutter: BottomNavigationBar vs NavigationBar
Migrating from BottomNavigationBar to the Material 3 NavigationBar: property mapping table, labelBehavior, NavigationBarThemeData, a decision guide and an adaptive shell.
Boss Suites Nana: 7 Nights in Bangkok for 4,500 TL
Our Boss Suites Nana hotel experience: deposit details, room cleanliness, breakfast cost, and why Nana is a convenient area for staying in Bangkok.
Vasu Exchange Bangkok: Rates, Location and Our Experience
We exchanged 100 dollars for 3,252 baht at Vasu Exchange near Nana, Bangkok. Rates, location, and what to watch out for when changing money.
How to Find the Best Swift Teacher? 2026 Guide
Before you pay for Swift or iOS tutoring: what to ask in a trial lesson, SwiftUI or UIKit, a sensible learning order, and when tutoring is not worth it.
.NET Expert Teacher Selection: C# and ASP.NET Education Guide
Choosing a C# and .NET teacher or course: trial lesson questions, warning signs, when private lessons are not worth it, and a realistic learning order.
Best Flutter Teacher Selection: Mobile App Expert Guide
Private Flutter tutor, video course or bootcamp? How to judge a teacher in a trial lesson, what order to learn in, and when tutoring is not worth it.
Algorithm Teacher: Data Structures and Algorithm Analysis
How to choose a tutor for data structures and algorithms: what to ask in a trial lesson, exam versus interview prep, and the order to study topics in.
Top 5 Most Used Flutter Widgets in 2026 (Detailed Guide)
Discover the 5 most critical widgets used in 90% of Flutter projects. Real project experiences, performance tips, and best practices for 2026.
Top 5 Biggest Mistakes Developers Make (And How to Fix Them)
Even senior developers fall into these 5 critical traps. Discover experience-backed tips that will save your codebase and your career.
Top 3 Programming Languages You Must Learn in 2026
As the AI revolution transforms the tech industry, these 3 popular programming languages will secure your career and double your market value.
How to Start Programming in 2026: A Complete Beginner's Roadmap
Want to learn programming but don't know where to start? The 2026 roadmap that works: the right language, resources and traps to avoid.
Flutter vs React Native: Which Is Better in 2026?
Can't decide between Flutter and React Native? Compare real performance, career opportunities and hands-on project experience.
Becoming a Developer in 2026: The Truths Nobody Tells You
Is becoming a developer really as easy as people say? Salaries, job hunting, AI's real impact, and career challenges — facing the honest realities of 2026.
Flutter Hero Animation and Page Transition Effects
Make your Flutter app professional and fluid with Hero animations and custom page transition effects. SlideTransition, FadeTransition, ScaleTransition and more.
Flutter Explicit Animations: AnimationController Guide
Create professional animations in Flutter with AnimationController, Tween, and AnimatedBuilder. Learn all the details of explicit animations.
Flutter: Zero Effort, Maximum Impact with Implicit Animations
Add professional animations without writing code using AnimatedContainer, AnimatedOpacity, AnimatedPositioned and more.
Introduction to OOP: Why Procedural Programming Falls Short
The journey from procedural to object-oriented programming: escaping spaghetti code and turning real problems into maintainable code.
C# Constructor: The Hidden Hero of Object Creation
What is a constructor and why do you need it? Default, parameterized and overloaded constructors explained with real examples.
C# Class and Object: Blueprint vs Product
Learn the core OOP building blocks, Class and Object, through the cake mold analogy, with Property, Method and Instance examples.
C# Access Modifiers: Lock the Doors or Leave Them Open?
What are public, private, protected and internal? How Getter/Setter methods secure data, explained with a bank account example.
Flutter: Real-Time Data Streams with StreamBuilder
Using StreamBuilder in Flutter, difference between Stream and Future, real-time data streams, and creating custom streams with StreamController.
Flutter: Modern State Management with Riverpod
State management with Riverpod package in Flutter, Provider vs Riverpod comparison, StateNotifier, StateProvider and best practices.
Flutter: State Management with Provider
State management with Provider package in Flutter, ChangeNotifier, Consumer, MultiProvider usage and best practices.
Flutter: ListView Widget Usage
A practical Flutter ListView guide: lazy lists with builder, separated, itemExtent, the real cost of shrinkWrap and fixing the unbounded height error.
Flutter: GridView Widget Usage
A practical Flutter GridView guide: count, extent and builder, the two grid delegates, the childAspectRatio overflow error and the real cost of shrinkWrap.
Flutter: Asynchronous Listing with FutureBuilder
A Flutter FutureBuilder guide: reading snapshot states in the right order, the create-the-Future-in-build mistake, the initState fix and refreshing with setState.
Flutter: TabBar and TabBarView Usage
Flutter TabBar and TabBarView: DefaultTabController vs your own TabController, keeping tab state alive, Material 3 settings, and common mistakes.
Flutter: SnackBar and SnackBarAction Usage
Flutter SnackBar with ScaffoldMessenger: undo actions, floating style, the queue problem and context errors after an await, all fixed.
Flutter: PopupMenuButton Usage and Menu Structures
Flutter PopupMenuButton for overflow menus: type-safe enums, onSelected vs onTap, a list row scenario and the mistakes to avoid.
Flutter: GestureDetector Usage and Touch Events
Tap, drag and pinch events with Flutter's GestureDetector: how it differs from InkWell, HitTestBehavior, common mistakes and a zoomable photo example.
Flutter: Form Widget and Input Validation
Flutter Form and TextFormField validation: validate() vs save(), autovalidateMode, focus handling, controller disposal and a complete login form.
Flutter: DropdownButton Usage and Features
Flutter DropdownButton and DropdownButtonFormField, the Material 3 DropdownMenu, a dependent dropdown scenario and the value assertion fix.
Flutter: Drawer Widget and Side Menu Usage
Build a side menu with Flutter Drawer: basic setup, the Material 3 NavigationDrawer, closing the menu before navigating, and the Scaffold.of context fix.
Flutter: Card Widget and Design Usage
Flutter Card guide: Material 3 Card.filled and Card.outlined, clipBehavior with images, tappable cards with InkWell, common mistakes and a product card.
Flutter: BottomNavigationBar Usage
Flutter BottomNavigationBar: currentIndex in state, keeping page state with IndexedStack, fixed vs shifting, the vanishing-items bug and a cart badge example.
Flutter: AppBar Widget and Customization
A practical Flutter AppBar guide: title, leading, actions and bottom, the Material 3 scrolled-under color change, and fixes for common mistakes.
Flutter: AlertDialog Usage and Customization
Flutter AlertDialog for confirmations, input and adaptive dialogs, plus fixes for context.mounted, StatefulBuilder and overflow bugs.
Flutter: Date and Time Pickers (DatePicker & TimePicker)
Flutter showDatePicker and showTimePicker: date ranges, localized calendars, context.mounted, an appointment scenario and the off-by-one-day bug.
Flutter: Using SingleChildScrollView and ScrollView
A Flutter SingleChildScrollView guide: when Column plus scroll view is right, the keyboard overflow error, the Expanded unbounded height problem and the IntrinsicHeight fix.
Flutter: Input Widgets and Status Indicators
When to use Switch, Checkbox, Radio, Slider and SegmentedButton in Flutter, plus progress indicators, common mistakes and a sample settings screen.
Flutter: Using FloatingActionButton (FAB)
Flutter FloatingActionButton: M3 sizes, extended FAB, positioning, hiding on scroll, the heroTag clash error and a reminders screen example.
Flutter Life Cycle: StatefulWidget and AppLifecycleState
Understanding Flutter StatefulWidget life cycle methods and application life cycle management. Using initState, dispose, didUpdateWidget, and setState.
Navigation and Data Transfer Between Pages in Flutter
Using Navigator in Flutter for page navigation, data transfer, and back stack management. push, pop, pushReplacement methods.
Creating and Setting Up App Icons in Flutter
How to add custom icons for both Android and iOS in your Flutter app? Automatic icon generation with flutter_launcher_icons package.
Introduction to Swift: Optionals, Guard Let and If Let Usage
After Flutter, I started learning Swift for iOS development. Sharing Optionals and safe unwrapping methods, one of the first concepts I encountered.
Flutter: Flexible Spaces with Spacer Widget
Creating flexible spaces inside Row and Column with the Spacer widget and things to watch out for.
Flutter: Sizing and Spacing with SizedBox
Sizing operations and creating invisible spaces with the SizedBox widget.
Flutter: Inner Space Management with Padding
Creating inner space around widgets with the Padding widget and using EdgeInsets.
Flutter: Screen-Based Scaling with MediaQuery
Sizing by screen with MediaQuery.sizeOf, paddingOf and textScalerOf; when LayoutBuilder or FractionallySizedBox is the better tool, and the common mistakes.
Flutter: Space Control with mainAxisSize
mainAxisSize decides how much room a Row or Column takes on its main axis. max vs min, how constraints interfere, and the usual mistakes.
Flutter: Screen Size-Based Design with LayoutBuilder
Creating dynamic and responsive designs for different screen sizes with the LayoutBuilder widget.
Flutter: Expanding Space with Expanded Widget
A deep dive into Expanded: how the flex ratio is computed, nesting, why it only works inside Row and Column, and the three errors you see most often.
Flutter: Creating Our Own Widgets
Writing custom widgets in Flutter: const constructors and super.key, required and optional parameters, widget class vs helper method, and common mistakes.
Flutter: Detailed Usage of Center Widget
Centering objects with the Center widget and using Center in different scenarios.
Flutter: Fine Alignment Operations with Align Widget
Detailed alignment operations and Alignment properties relative to the area it's in with the Align widget.
Flutter: Adding Images - Assets and Image.asset
Adding images to Flutter project, pubspec.yaml configuration and using the Image.asset widget.
Flutter Basics: Widget Tree, Row, Column and Stack
After learning Dart, I finally transitioned to Flutter. On my first day, I'm learning the widget tree, Row, Column and Stack structures.
Dart Error Handling: Try-Catch and Asynchronous Operations
Learning error handling with try-catch and asynchronous programming with async-await in Dart. Future and await concepts.
Dart Collections: Data Management with List, HashSet and HashMap
Learning to work with data structures in Dart. Discovering the differences and use cases between List, HashSet and HashMap.
Dart Interface and Implements - Adding Extra Features to Classes
Learning how to add extra features to our classes with abstract classes and the implements keyword.
Dart Inheritance and Polymorphism - Parent-Child Relationship
Learning inheritance and polymorphism, one of the most important concepts of OOP. Looking at what we can do with extends, override and super keywords.
Dart Enum and Composition - How to Organize Code?
Continuing my Dart learning journey. Today I learned about enum structures and composition. Explaining with real-life examples.
Dart Type Conversions and Static Variables Explained
Learning Dart basics while starting Flutter. Sharing what I learned today about type conversions and static variables.
Getting Started with Flutter Mobile App Development
Flutter from zero: installation overview, flutter doctor, creating and running your first project, project structure, hot reload and what to learn next.